We have successfully developed procedures to solubilize LH/hCG receptors (LHR) from porcine and rat ovaries in high yield. Porcine and rat LHR have been purified to apparent homogeneity by a two-step hCG-Sepharose affinity chromatographic procedure. The predominant subunit of LHR so purified has a molecular weight of 70,000 - 80,000 Daltons under denaturing reducing conditions. During the proposed grant period, the physico-chemical and biological properties of purified rat and porcine LHR will be compared. Antibodies to porcine LHR will be developed in rabbits, and rat LHR will be injected into mice with the goal of producing a monoclonal antibody to rat LHR. Antibodies will be characterized by immunochemical techniques and their biological properties will be tested using isolated receptors, membranes, cultured cells and the whole animal. The molecular basis of receptor regulation by hormones will be analyzed through direct measurements of rates of synthesis and degradation of LHR by specific immunoprecipitation methodology. Receptor antibodies will provide a superb analytical tool for investigation of the molecular biology of LHR synthesis, processing and turnover. LHR antibodies will not only be critical tools for investigation of ovarian physiology at the molecular level, but also may have significant practical application in immunocontraception and in understanding infertility of ovarian origin and in the development of monoclonal LHR antibody-drug conjugates which may be useful in therapy of ovarian cancer.